Medicament delivery device

ABSTRACT

A dose setting mechanism for a medicament delivery device is presented having a pinion mounted to a locking member where the axis of rotation of the pinion is offset and parallel to the longitudinal axis of the housing containing the dose setting components. Primary and secondary dose members are engaged with the pinion to indicate a set dose of medicament.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 14/449,671, filed Aug. 1, 2014, which is a continuation of U.S.patent application Ser. No. 13/896,639, filed May 17, 2013, now U.S.Pat. No. 8,827,962, which is a continuation of U.S. patent applicationSer. No. 13/203,040, filed Jan. 31, 2012, now U.S. Pat. No. 8,491,536,which is a U.S. National Phase Application pursuant to 35 U.S.C. §371 ofInternational Application No. PCT/US2010/060022 filed Dec. 13, 2010,which claims priority to Swedish Patent Application No. 0950958-9 filedon Dec. 15, 2009. The entire disclosure contents of these applicationsare herewith incorporated by reference into the present application.

TECHNICAL AREA

The present invention relates to a medicament delivery device comprisinga dose setting function.

BACKGROUND

Medicament delivery devices such as injectors are sometimes providedwith functions where a specific dose can be set by the user, which dosemay be varied within a range.

Quite often this dose setting function is performed by turning a knob orwheel at the distal end of the device whereby it is moved in the distaldirection. When performing a subsequent injection, the knob is pushedlinearly in the proximal direction. One such injector is disclosed inthe document U.S. Pat. No. 6,221,053 in which the distal dose knob ofthe injector is threaded out of a rod barrel tube as a dose is set. Thusthe distance the knob is moved in the distal direction is directlyrelated to the dose quantity to be delivered.

One drawback with that type of solution is that if larger doses are tobe delivered the dose knob has to be moved quite a long distance in thedistal direction, which means that it might be difficult for a user topush the dose knob in the proximal direction during injection.

SUMMARY

The aim of the present invention is to remedy the drawbacks of the stateof the art medicament delivery devices and to provide a device by whichit is possible to set a desired or required dose in a simple andintuitive way.

This aim is obtained by a medicament delivery device according to thefeatures of the independent patent claim. Preferable embodiments of theinvention are subject of the dependent patent claims.

According to a main aspect of the invention it is characterised by amedicament delivery device comprising a housing having opposite distaland proximal ends; a medicament container holder releasably connected tosaid housing; a medicament container arranged inside said medicamentcontainer holder; a threaded plunger rod arranged to pass through afirst inner wall of the housing and arranged to act on a stopper in themedicament container; a lead screw member coaxially connected to thethreaded plunger rod by co-acting first slidably-and-rotatably-lockedmeans; wherein said device further comprises a nut coaxially connectedto the threaded plunger rod by a treaded engagement between them,connected to the lead screw member by co-actingnon-slidable-and-rotatable means, and connected to the housing byco-acting second slidably-and-rotatably-locked means; a primary dosemember coaxially rotatable on the lead screw member when the device isin a non-activated state and connected to the lead screw member byco-acting third slidably-and-rotatably-locked means when the device isin an activated state; a locking member fixedly connected to the housingand releasably connected to the lead screw member by co-acting lockingmeans; a first spring force means arranged between the first inner wallof the housing and the nut, wherein the first spring force means is in apre-tensioned state when said locking means are engaged and the deviceis in the non-activated state; a secondary dose member rotatablyconnected to said primary dose member via a pinion gear; dose settingmeans connected to the primary dose member by co-acting fourthslidably-and-rotatably-locked means, such that when the device is to beset from the non-activated state to the activated state, the dosesetting means are manually manipulated in a pre-determined direction,whereby the locking means are released and the lead screw member isdistally moved a pre-determined distance by the first spring force meansindependent of the size of a dose to be set.

According to a further aspect of the invention, said primary and saidsecondary dose members are provided with indicia.

According to another aspect of the invention, the locking meanscomprises a proximally pointing and radial flexible lever arranged onthe locking member, an annular ledge on the circumferential surface ofthe lead crew member, and the circumferential inner surface of thesecondary dose member; such that when the first spring force means is ina pre-tensioned state, the circumferential inner surface of thesecondary dose member forces the flexible lever radial inwardly incontact with the ledge; and when the dose setting means are manuallymanipulated, the secondary dose member is rotated to a position whereinthe flexible lever is radial outwardly flexed into a longitudinal grooveon the inner circumferential surface of the secondary dose member.

According to yet a further aspect of the invention, the locking membercomprises on its distal circumferential surface a distally pointing stopmember, and wherein the secondary dose member comprises on its proximalcircumferential surface a first and a second proximally pointing stopmembers arranged to interact with the stop member of the locking member.

According to yet another aspect of the invention, thenon-slidable-and-rotatable means comprises ratchet arms and radialinwardly directed arms on the nut, grooves on the outer circumference ofwheels on the proximal end of the lead screw member, and an annulargroove between the wheels, wherein the ratchet arms cooperate with thegrooves for giving an audible signal when the lead screw member isrotated; and wherein the radial inwardly directed arms cooperate withthe annular groove such that the lead screw member and the nut areslidably locked and rotatable in relation to each other.

According to a further aspect of the invention, the firstslidably-and-rotatably-locked means comprises radial inwardly directedledges on the inner surface of the proximal end of the lead screwmember, and longitudinally extending grooves on the plunger rod, whereinthe grooves cooperate with the radial inwardly directed ledges such thatthe lead screw member and the plunger rod are rotationally locked andslidable in relation to each other.

According to another aspect of the invention, the secondslidably-and-rotatably-locked means comprises grooves on the outercircumferential side surface of the nut, and longitudinal ribs on theinner surface of the housing, wherein the grooves cooperate with thelongitudinal ribs such that the nut and the housing are rotationallylocked and slidable in relation to each other.

According to yet a further aspect of the invention, the thirdslidably-and-rotatably-locked means comprises splines on the outercircumferential surface of the lead screw member, and correspondingsplines arranged on the inner circumferential surface of the primarydose member, wherein the splines cooperate with corresponding splinessuch that the lead screw member and the primary dose member arerotationally locked and slidable in relation to each other.

According to yet another aspect of the invention, the dose setting meanscomprises a clutch plate provided with a first annular ratchet, a dosesetting knob provided with a second annular ratchet, and a second springforce means arranged between a second inner wall of the housing and aproximal surface of the clutch plate, such that clutch plate is distallyurged and the first and the second ratchet are abutting each other, andwhich dose setting knob protrudes through the distal end of the housing.

According to a further aspect of the invention, the fourthslidably-and-rotatably-locked means comprises longitudinally extendinggrooves on the outer circumferential surface of the primary dose member,and radial inwardly directed protrusions on the inner surface of theclutch plate, wherein the longitudinally extending grooves cooperatewith radial inwardly directed protrusions such that the primary dosemember and the clutch plate are rotationally locked and slidable inrelation to each other.

According to another aspect of the invention, the plunger rod isarranged to be proximally moved a distance corresponding to a set doseto be delivered by manually manipulating the dose setting knob when thedevice is in the activated state.

There are a number of advantages with the present invention. Because thelead screw, e.g. the manually operating delivery means, protrudesoutside the housing with the same length independent of the set dosequantity the manual dose delivery operation is the same independent ofset dose, i.e. the lead screw member has always the same position when adose has been set.

Compared to the state of the art medicament delivery devices, thissolution is a great advantage for the user or patient who suffers ofdexterity problems. Also when not in use, the lead screw member isinside the medicament delivery device and locked. The unlocking of thelead screw member is performed when said dose setting knob is turned toan initial position, preferably a zero-dose position.

These and other features and advantages will become apparent from thedetailed description and from the accompanying drawings.

BRIEF DESCRIPTION OF THE FIGURES

In the detailed description reference will be made to the accompanyingdrawings in which

FIGS. 1a,b are a cross-sectional view of a medicament delivery deviceaccording to the present invention;

FIG. 2 is an exploded view of the medicament delivery device of FIGS. 1a,b;

FIG. 3 is a detailed view of a dose-setting mechanism comprised in thepresent invention;

FIG. 4 is a further detailed view of the dose-setting mechanismcomprised in the present invention; and

FIG. 5 is yet a further detailed view of the dose-setting mechanismcomprised in the present invention; and

FIGS. 6, 7 a, 7 b, 8 a, and 8 b are cross-sectional view of differentfunctional positions.

DETAILED DESCRIPTION

In the present application, when the term “distal part/end” is used,this refers to the part/end of the injection device, or the parts/endsof the members thereof, which under use of the injection device islocated the furthest away from the medicament injection site of thepatient. Correspondingly, when the term “proximal part/end” is used,this refers to the part/end of the injection device, or the parts/endsof the members thereof, which under use of the injection device islocated closest to the medicament injection site of the patient.

The medicament delivery device 10 according to the drawings comprises agenerally elongated housing 12 having opposite distal and proximal ends.The elongated housing being e.g. divided in a proximal 12 a and a distalpart 12 b. The proximal end of the housing is arranged with fasteningmeans such as e.g. threads 14 on its inner surface, which fasteningmeans cooperate with corresponding fastening means such as outwardlythreads 16 on a distal end of a medicament container holder 18,providing a releasable connection. Inside the medicament containerholder a medicament container 20 can be placed. The proximal end of themedicament container holder 18 is arranged with a threaded neck 22 forconnection of a medicament delivery member such as an injection needle24, a mouthpiece, a nozzle or the like, FIG. 2.

When received by a user, the medicament delivery device 10 is providedwith a releasably attachable protective cap 26. At the distal end of themedicament container holder a sleeve-shaped container support 28 isinserted for holding and supporting the medicament container 20 wheninserted, FIG. 2. At the proximal end of the housing a first inner wall30 is arranged, which wall is provided with a central passage 32, FIG.1b . The central passage is arranged with a distally directed tubularflange 34, FIG. 1a . A threaded plunger rod 36 extends in thelongitudinal direction through the central passage 32 with a proximalend adjacent a stopper 38 inside said medicament container 20, FIG. 1a .The proximal end of the plunger rod 36 is further arranged with aplunger rod tip 40, FIG. 2.

The device further comprises a lead screw member 58 coaxially connectedto the threaded plunger rod by co-acting firstslidably-and-rotatably-locked means; and a nut 44 coaxially connected tothe threaded plunger rod by a treaded engagement between them. The nutalso being connected to the lead screw member by co-actingnon-slidable-and-rotatable means, and to the housing by co-acting secondslidably-and-rotatably-locked means.

The first slidably-and-rotatably-locked means comprises radial inwardlydirected ledges 57 on the inner surface of the proximal end of the leadscrew member, and longitudinally extending grooves 42 on the plungerrod, FIG. 2, wherein the grooves cooperate with the radial inwardlydirected ledges 57 such that the lead screw member and the plunger rodare rotationally locked and slidable in relation to each other.

The non-slidable-and-rotatable means comprises ratchet arms 50 andradial inwardly directed arms 51 on the nut 44, grooves 56 on the outercircumference of wheels 54 on the proximal end of the lead screw member,and an annular groove 53 between the wheels 54, wherein the ratchet arms50 cooperate with the grooves 56 for giving an audible signal when thelead screw member is rotated; and wherein the radial inwardly directedarms 51 cooperate with the annular groove 53 such that the lead screwmember and the nut are slidably locked and rotatable in relation to eachother, FIG. 3.

The second slidably-and-rotatably-locked means comprises grooves 52 onthe outer circumferential side surface of the nut 44, FIG. 3, andlongitudinal ribs on the inner surface of the housing (not shown),wherein the grooves cooperate with the longitudinal ribs such that thenut and the housing are rotationally locked and slidable in relation toeach other.

The nut 44 comprises a threaded central passage 46 which cooperates withthe threads of the plunger rod, FIG. 2, thereby forming the threadedengagement between them.

The device also comprises a primary dose member 66 coaxially rotatableon the lead screw member when the device is in a non-activated state andconnected to the lead screw member by co-acting thirdslidably-and-rotatably-locked means when the device is in an activatedstate. The third slidably-and-rotatably-locked means comprises splines60 on the outer circumferential surface of the lead screw member; andcorresponding splines 64 arranged on the inner circumferential surfaceof the primary dose member, wherein the splines 60 cooperate withcorresponding splines 64 such that the lead screw member and the primarydose member are rotationally locked and slidable in relation to eachother, FIGS. 2 and 3.

The device further comprises:—a locking member 96 fixedly connected tothe housing and releasably connected to the lead screw member byco-acting locking means;—a first spring force means 48 arranged betweenthe first inner wall 30 of the housing and the nut, wherein the firstspring force means is in a pre-tensioned state when said locking meansare engaged and the device is in the non-activated state; and—asecondary dose member 90 rotatably connected to said primary dose member66 via a pinion gear 94, FIG. 3.

The device also comprises dose setting means connected to the primarydose member by co-acting fourth slidably-and-rotatably-locked means,such that when the device is to be set from the non-activated state tothe activated state, the dose setting means are manually manipulated ina pre-determined direction, whereby the locking means are released andthe lead screw member is distally moved a pre-determined distance by thefirst spring force means independent of the size of a dose to be set.

The dose setting means comprises a clutch plate 74 provided with a firstannular ratchet 76, a dose setting knob 84 provided with a secondannular ratchet 82, and a second spring force means 78 arranged betweena second annular inner wall 80 of the housing and a proximal surface ofthe clutch plate, such that clutch plate is distally urged and the firstand the second ratchet are abutting each other, and which dose settingknob protrudes through the distal end of the housing, FIGS. 1a and 4.The fourth slidably-and-rotatably-locked means comprises longitudinallyextending grooves 70 on the outer circumferential surface of the primarydose member 66, and radial inwardly directed protrusions 72 on the innersurface of the clutch plate 74, wherein the longitudinally extendinggrooves 70 cooperate with radial inwardly directed protrusions 72 suchthat the primary dose member and the clutch plate are rotationallylocked and slidable in relation to each other, FIGS. 2 and 3. The distalend of the lead screw member 58 protrudes through the dose setting knob84, and is at its distal end arranged with a dose injection button 86,FIGS. 2 and 7 b. Outside the dose injection button 86 a spin ring 88 isrotatably arranged, FIG. 2.

The locking means comprises:—a proximally pointing and radial flexiblelever 102 arranged on the locking member,—an annular ledge 62 on thecircumferential surface of the lead crew member, and—the circumferentialinner surface of the secondary dose member, FIG. 2. The secondary dosemember 90 is also arranged with teeth 92 arranged around itscircumference, which teeth cooperate with teeth on the pinion gear 94,which is journalled in the housing as well as the locking member 96 viaa locking lever bracket, FIG. 3. Further the primary dose member 66 isarranged with a gear segment 98, which also cooperate with the piniongear 94, FIG. 3. A certain part of the lead screw member 58 is arrangedwith the splines 60 on its outer circumferential surface, FIG. 2; whichsplines have a lesser diameter than the proximal part of the lead screwmember, thereby creating the annular ledge 62, FIG. 2. The lockingmember 96 also comprises on its distal circumferential surface adistally pointing stop member 95, and the secondary dose member 90comprises on its proximal circumferential surface a first 91 and asecond 93 proximally pointing stop member arranged to interact with thestop member of the locking member, FIG. 4.

The proximal part of the primary dose member 66 and the secondary dosemember 90 are arranged with a circumferential band containing numbers orindicia 68 which are used to indicate dose size through a dose window onthe housing, as will be explained below, FIG. 3.

The device is intended to function as follows. When delivered to theuser, the device is in the non-activated state wherein a medicamentcontainer 20 has been inserted in the medicament container holder 18 inthe proximal end of the device, FIG. 1, the first spring force means isin a pre-tensioned state and said locking means are engaged, wherein thecircumferential inner surface of the secondary dose member 90 forces theflexible lever 102 radial inwardly in contact with the ledge 62.

When the device is to be used the protective cap 26 is removed and thedose setting means are manually manipulated for setting the device fromthe non-activated state to the activated state by rotating the dosesetting knob 84 counter clockwise until activating indicia as e.g. twozeros are visible through the window of the housing. The rotation of thedose setting knob 84 causes the clutch plate 74 and thereby the primarydose member 66 to rotate due to the engagement between the co-actingfourth slidably-and-rotatably-locked means, and due to the connectionbetween the first 76 and the second 82 ratchets. However, the lead screwmember is not rotated since the third slidably-and-rotatably-lockedmeans 60, 64 are not in engagement, i.e. the splines 60 on the outercircumferential surface of the lead screw member and the correspondingsplines 64 arranged on the inner circumferential surface of the primarydose member 66 are not in engagement. The secondary dose member 90 alsorotates due to the connection between the gear segment 98 of the primarydose member 66 and the teeth 92 of the secondary dose member 90 throughthe pinion gear 94. The rotation of the secondary dose member 90 isstopped when its second proximally pointing stop member 93 abuts thedistally pointing stop member 95. This causes a longitudinal groove onthe inner circumferential surface (not shown) of the secondary stopmember to be aligned with the flexible lever 102 whereby the flexiblelever is radial outwardly flexed into the groove and thereby moved outof contact with the ledge 62 of the lead screw member 58. This causesthe lead screw member 58 to move a pre-determined distance in the distaldirection due to the force of the spring 48 acting on the nut 44, whichin turn is attached to the lead screw member 58. The splines 60 on theouter circumferential surface of the lead screw member and thecorresponding splines 64 arranged on the inner circumferential surfaceof the primary dose member are then engaged to each other. Because ofthe movement of the nut 44, the plunger rod 36 is also moved. The distalend of the lead screw member 58 and its dose injection button 86 nowprotrude distally out of the housing said predetermined distance andindependent of the size of the dose to be set.

The device is now in the activated state and ready for setting arequired dose of medicament, FIGS. 7a and 7 b.

When setting a dose, the plunger rod is arranged to be proximally moveda distance corresponding to a set dose to be delivered by manuallymanipulating the dose setting knob. The dose setting knob 84 is rotatedin the clockwise direction which also rotates the primary dose member 66clockwise indicating the dose that is being dialed. At the same time theprimary dose member 66 rotates the lead screw member 58 clockwise due tothe engagement between the co-acting third slidably-and-rotatably-lockedmeans 60, 64; and the lead screw rotates the plunger rod due to theengagement between the co-acting first slidably-and-rotatably-lockedmeans, driving the plunger rod 36 through the nut 44 because of thethreaded engagement between them, thereby moving the plunger rod 36proximally. The secondary dose member 90 also rotates due to theconnection between the gear segment 98 of the primary dose member 66 andthe teeth 92 of the secondary dose member 90 through the pinion gear 94.The rotation of the secondary dose member 90 is stopped when its firstproximally pointing stop member 91 abuts the distally pointing stopmember 95, which indicates the maximum dose the device can deliver e.g.two indicia as e.g. a seven and a zero are visible through the dosewindow. In any case, the set dose is visible through the dose window ofthe housing. At this point the device is ready for an injection.

Moreover, if the user attempts to dial past the maximum dose the devicecan deliver or if the user attempts to dial pass the activating indicia,the connection between the first annular ratchet 76 and the secondannular ratchet will function as a clutch.

When the dose is set, a medicament delivery member 24 is attached to theproximal end of the device, such as e.g. an injection needle. It ishowever to be understood that other types of medicament delivery membersmay be used in order to deliver a dose of medicament. The medicamentdelivery member is then placed at the delivery site and the user pressesthe dose injection button 86 in the proximal direction the predetermineddistance that the distal end of the lead screw member 58 and its doseinjection button 86 protrudes distally out of the housing and which saidpredetermined distance is independent of the size of the dose to bedelivered. This causes the lead screw member 58 to move in the proximaldirection as well as the nut 44 and the plunger rod 36. This proximalmovement of the plunger rod 36 causes it to act on the stopper 38 of themedicament container 20 whereby a dose of medicament is expelled throughthe medicament delivery member 24. When the lead screw member 58 hasreached a certain distance inside the housing, the flexible lever 102 ofthe locking member is again moved in contact with the ledge 62 of thelead screw member 58, FIG. 8. The medicament delivery member may now beremoved and discarded.

When a subsequent dose is to be performed, the above described procedureis performed and can be repeated until the medicament container isemptied.

It is to be understood that the embodiment described above and shown inthe drawings is to be regarded only as a non-limiting example of theinvention and that it may be modified in many ways within the scope ofthe patent claims.

The invention claimed is:
 1. A dose setting mechanism for a medicamentdelivery device comprising, a housing having a longitudinal axis; alocking member rotationally and slidably fixed to the housing andreleasably engaged with a lead screw; a dose member arranged coaxiallyand slidable with respect to the lead screw such that the dose member isrotatable relative to the lead screw when the dose setting mechanism isin a non-activated state and where the dose member is slidably connectedand rotatably fixed to the lead screw when the dose setting mechanism isin an activated state; the lead screw is coaxially arranged and engagedwith the locking member when dose setting mechanism is in thenon-activated state; a plunger rod rotationally fixed to the lead screw;a nut threadedly connected to the plunger rod and slidably locked to thelead screw; and a dose knob rotationally fixed to the dose member thatis in clutched engagement with the lead screw, where the dose knob anddose member are rotationally fixed to the lead screw when the dosesetting mechanism is in the activated state, and wherein the lockingmember is disengaged from the lead screw when the dose setting mechanismis in the activated state and the locking member is engaged with thelead screw when the dose setting mechanism is in the non-activatedstate.
 2. The dose setting mechanism of claim 1 where the dose settingknob is connected to the dose member such that when the dose settingmechanism is transformed from the non-activated state to the activatedstate, the dose setting knob is manually manipulated in a pre-determineddirection, whereby the locking member is released and the lead screwmember is distally moved a pre-determined distance by a biasing forceindependent of the size of a dose to be set.
 3. The dose settingmechanism of claim 2 where the biasing force is in a distal directionand is generated by a compression spring in a pre-tensioned state. 4.The dose setting mechanism of claim 1 further characterized in that thelocking member comprises a flexible lever configured to engage a ledgeon the lead screw when the dose setting mechanism is in thenon-activated state.
 5. The dose setting mechanism of claim 1 furthercharacterized in that the locking member has a proximal enlarged platewith a distally projecting stop member.
 6. The dose setting mechanism ofclaim 5 further characterized in that the dose member has a stop memberthat interacts with distally projecting stop member on the lockingmember during dose setting.
 7. The dose setting mechanism of claim 1further characterized in that the lead screw and the dose member arearranged and configured such that the lead screw can slide axiallyrelative to the dose member during transition from the non-activatedstate to the activated state.
 8. The dose setting mechanism of claim 1further characterized in that a ratchet is between proximal end of thelead screw and the nut such that rotational movement of the lead screwrelative to nut generates an audible signal during dose setting.
 9. Thedose setting mechanism of claim 8 where the audible signal is directlyrelated to each unit dose set.
 10. The dose setting mechanism of claim 1further characterized in that the nut comprises grooves on an outercircumferential side face that engage longitudinal ribs on an innersurface of the housing to rotationally lock the nut to the housing andallow the nut to slide relative to the housing when the dose settingmechanism transitions from the non-activated state to the activatedstate.
 11. The dose setting mechanism of claim 1 further comprising abiasing member that is a spring located between an inner wall of thehousing and a proximal end of the nut and is in a pre-tensioned statewhen the dose setting mechanism is in the non-activated state and thelocking member is engaged with the lead screw.
 12. The dose settingmechanism of claim 1 further characterized in that the dose member isarranged with a circumferential band containing indicia indicative of aset dose.
 13. The dose setting mechanism of claim 12 where the housingfurther comprises a dose window that is configured to allow viewing ofthe indicia.